egerton



H. C. EGERTON. TELEPHONE AMPUFIER. APPLICATION FILED mu: 1. IEHE.

Patented Apr. 20, 1920.

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H. C. EGERTON.

TELEPHONE AMPLIFIER. APPLICATION mm mm: z, 1916.

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- Af/f) HENRY G. EGEBTON, OF PASSAIO, NEW JERSEY,

COMPANY, INCORPORATED, OF

NEW YORK, N. Y., A

ASSIGNOR '10 WESTERN ELECTRIC CORPORATION 03' NB BK.

TELEPHONE-AMPLIFIER.

Specification of Letters Patent.

Patented Apr. 20, 1920.

Application filed June 7, 1916. Serial No. 102,205.

To all whom it may concern:

Be it known that I, HENRY O. Eonnron, a citizen of the United States, residing at Passaic, in the county of Passaic and State of New Jerse have invented certain new and useful mprovements in Telephone- Amplifiers, of which the following is a full, clear, concise, and exact description.

This invention relates to telephone instruments, and more particularly to improvements in devices for relaying telephonic currents, or for reproducing such currents aurally, all in a manner to respectively secure am lifications thereof and articulate sounds o relativel considerable volume.

The principal object of this invention is and to improve the working efto simplif telephone devices of this characficiency o ter.

In accordance with this invention, in substitution of working bearings, the armature of an electromagnetic structure is fixed to work against torsional flexing stresses thereby set up in a rigidly supported member, all in response to telephonic currents suitably applied to the device. Such motor telephone currents may be either relayed or repro-. duced aurally by utilizing the resulting movements or vibrations of the armature to respectively operate telephone transmitting or receiving diaphra ms.

This invention is i lustrated in the accompanying drawings, in which Figure 1 is a side sectional vlew of the instrument arranged in a manner to operate one transmitter button.

Fig. 2 is a side view partially in section correspondin with the next right-hand face of the assem ly shown in Fig. 1.

1*ig.f3 is a perspective, with the outer casing removed, of the assembly shown'in Figs. 1 and 2.

r igs. 4 and 5 are respectivelv the same as Figs. 1 and 2, except that the structure is modified to operate two transmitter buttons. Big. 6 is a combined sectional and diagrammatic side view of the electroma etic structure with operatin circuits an also illustrating a; method 0 applying the device to operateediaphragm to thereby convert telephone currents into articulate sounds.

In describing with the drawings,

this iiitehtion in connection similar characters of refthereby causing erence will be used to indicate corresponding parts in all the figures.

n the present. embodiment of this invention, the instrument comprises a supporting base 5, an outer protective casing 6 and an inner framework 7, all constructed, preferably, of suitable non-magnetizablc metal. An Eshaped magnet frame 9 carries on its pole members 10 and 12 sensitizing or polarizing windings 13 and 14, respectively, and also windings 15 and 16, respectively, for telephonic currents. An armature 20 is fixed, intermediate its ends, to the inner edge ofn U-shapcd member 21, the ends of which are reinforced by means of details 22. Slots 23, formed in t e frame 7, are adapted to receive the reinforced ends of the armature support 21, and when these are entered therein to a depth for securing a predetermined air-gap adjustment between the face of the armature 20 and the pole members 10, 11 and 12 of the magnet frame 9, these ends may be firmly clamped at such point by means of set screws 24.

In operating this device, a source of unidirectional current 8 applied, as shown, to the windings 13 and 14, thereby produces magnetism of uniform sign in the outer pole members '10 and 12, each of which then acts accumulatively with the oppositel magnetized central ole member 11. The rela-. tion of the windings 15 and 16, one with the other, is such that when telephonic currents are applied thereto, as from an induction coil 17, worked by a distant transmitter 18 over the circuit shown, magnetism of respeetively opposite polarity will be accordingly set up in the pole members 10 and 12, such magnetic stresses to move the ends of the polarized armature 20 in opposite directions. The movements of the armature 20 correspond in direction and amplitude with the direction and strength of the applied telephonic currents. Therefore, a diaphragm 25 suitably supported at its periphery when attached to the armature 20, as by means of a member 26, will execute movements to transform such mechanical vibrations of the armature into articulate sounds.

In relayin telephonic currents, it has been found t at a granular carbon transmitter unit, such as shown in detailsection in Fig. 1, gives the best results.

This transisheld in mitter unit comprises a mounting block 30, preferably of brass, suitably secured to the base 5. Block 30 has a cylindrical cupshaped portion into which is tightly fitted a brass sleeve 31, having a portion 32 with large internal diameter and. a portion 33 of smaller internal diameter. A paper insulating sleeve 34 covers the inner surface of portion 32, while a coating 35 of electrically insulating but comparatively high heat conducting apan or enamel covers the inner surface of portion 33 over-running both edges as shown. A back electrode 36, preferably a carbon disk, is fitted into the portion 34 of sleeve 31 but is insulated therefrom by the paper sleeve 34, the japan and a mica washer 37. A frontelectrode 38, also in the form of a carbon disk is carried by and in electrical engagement with armature 20 and is separated from' sleeve 31 by a Washer 39 preferabl of felt. The chamber 40 thus formed by t e inner japanned walls of portion 33 of sleeve 31 and the front and back electrode 38 and 36 contains the usual comminuted material such as granulated carbon. This form of unit provides good insulation between the parts while, at the same time, the heat produced by the passage of current through the comminuted material is readily dissipated. The back electrode 36 place by a spring 41, which, engaging 'an insulated stud 42 to which is connected a suitable conductor 43, also forms a part of the electrical circuit of the trans mitter.

As shown in Figs. 4 and 5 of the draw ing, the armature" of-thi-s electromagnetic system may be conveniently adapted to operate a plurality of transmitter buttons, as 45 and 46, each of which may correspond with the transmitter button already described.

A plurality of terminals 47 suitably 'bushed and insulated from the base 5 on which they are, for convenience, mounted, serve as terminals for the various circuits of this device and as junction points to which exterior conductors may be connected.

What is'claimed is:

1. An electromagneticstructure comprising acore having a plurality of laterally spaced pole pieces, polarizing means for said core, a winding for actuating current associated with said core, supporting means,-

a resilient armature carrying member associated with said supporting means, and an armature fixed to said member positioned entirely to one side of said core overlying said pole pieces and normally maintained in a defipite airgap relation to said pole pieces by said member; said armature being movable in response to actuating currents in said win ing to vary such air gap relation against the torsional? said member. 3, .An electromagnetic structurecomprising a core having a plurality of laterally spaced pole pieces, polarizing means for said core, a winding for actuating current associated with said core, s a resilient armature carrying member fixed to said supporting means intermediate said pole pieces, and an armature fixed to saidv member positioned entirel to one side of said core overlying said p0 e pieces and normally maintained in a definite air gap-rela: tion to said pole pieces by said member; said armature being movable in response to actuating currents in said Winding to vary such an gap relation against the torsion of said member.

3. An amplifier comprising a core having a plurality of laterally spaced pole pieces, polarizing means for said core, a windin for actuating current associated with sai core, supporting means, a resilient armature carrying member fixed to said support means, an armature fixed to said menu.-. positioned entirely to one side of said core overlying said pole pieces and normally maintained in a definite air gap relation to said pole pieces riablc resistance ciated with said the side of said armature opposite to that presented to said pole piecespsaid armaturebeing movable in response to actuating currents in said winding to vary' such air gap relation against the torsion of said member and to correspondingly operate said resistance element.

4. A telephone amplifier comprising a core having a plurality oflaterally spaced pole pieces, polarizing means for said core a windin fortelephonic currents associated with said core, supporting means, a resilient armature carrying member carried by said supportin means, an armature fixed intermediate 0? its length to said member and overlying said pole pieces, and a pair of separate telephone transmitter elements one being operatively connected to one end of said armatureand the other operatively connected to the other end of said armature to providesimultaneous operation of both elementson movem t of said armature.

.5. A telephone amplifier com rising. a core having a plurality of laterally spaced pole pieces, polarizing means for said core a windin for actuating current associated with sai 1 core, supporting means, a resili ent armature carrying member fired to said sup ortin means, an armaturefixed interme late 0 its length to said member oven lying and extending beyond and a pair of separate transmitter elements one being operatively connected to one on of said armature be 011630118 of the pole pieces and the other ein operatively con- Iiected tothe other end 0 the armature beelement operatively assoyond another of the pole pieces to provide supporting mean by said member, and a vaarmature and arranged on said pole pieces,

simultaneous operation of both elements on movement of said armature.

6. A telephone amplifier comprising a core having a plurality of spaced pole pieces, polarizing means for said core a Winding for telephonic rurrents, supporting means, a resilient armature carrying member fixed to said supporting means, an armature fixed to said carrying member and positioned at one side of said core to overlie said pole pieres, said armature being movable to torsion said member in response to telephonic currents in said winding, and a pair of variable resistance elements, one serured to one end of' said arn'iature and the other secured to the other end of said armature, and both ope ated by said armature.

T. A telephone amplifier eomprising a core having a plurality of spaced pole pieres, polarizing means for said core. a winding for telephonic rurrents, supporting means a resilient armature rarrying memher fixed to said supporting means, an armature iixed to said carrying member and positioned at one sille of said core to overlie said pole pieees, said armature being movable to torsion said member in response to telephonic rurrents in said winding, and a pair of variable resist anee elements each comprising a front and a rea r eleetrode and having their respertire Front electrodes serured to opposite ends of said armature for movement therewith.

An electromagnetic strurture comprising a core having a plurality of spaced pole pieces, polarizing means for said core, supporting means, a Usha1'wed resilient carrying member having the legs thereof engaged by said supporting means, and an armature fixed to and transversely of' the base of said member and movable to torsion said member.

Tn witness whereof. I hereunto subscribe my name this 3rd day of June, A. D. 1916. 4

HENRY c. EGERTON. 

